Temporal and Spatial Characterization of an Infestation of Paratachardina lobata lobata (Hemiptera: Kerriidae), A New Invasive Pest in Florida

Nancy D. Epsky, Divina Amalin, Paul E. Kendra, Helena Puche, Catharine M. Mannion

Abstract


The lobate lac scale, Paratachardina lobata lobata (Chamberlin) was first found in south Florida in 1999. Reported hosts are present in the germplasm collection located at the USDA/ARS Subtropical Horticulture Research Station in Miami, and the scale was first found there in the summer of 2002. A study was initiated to determine the spatio-temporal dynamics of a lobate lac scale infestation at SHRS from Jul 2003 to Jul 2005. Numbers and percentages of viable adults, and reproductive success as indicated by ratio of nymphs to viable adults (<2 cm diam and 30 cm long branch sample) were recorded. There were 55 plants evaluated over the 80 hectares study site. Infestation increased from 42% of sampled plants at the start of the study to 75% at the end, and most of the plants had low or moderate levels of infestation (between 0 and 100 adults per 30 cm branch) over the course of the study. Percentage of non-viable adults dropped from 27% at the start of the study to 7% by the end of the study, and ratio of nymphs to viable adults dropped from 9% to 2%. Spatial analysis showed that initial infestations were along the eastern edge of the sampled area, with populations declining over the first half of the study but then increasing during the second half. Over the course of the study, heavy infestations (=100 scales per 30 cm branch) were found on only seven host plants. Among plants located in areas of high infestation probabilities, individual host susceptibility appeared to be the primary factor regulating infestation level.

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